Test strip devices are widely used in medical diagnostics. Such test strips provide simple portable devices that can be used to detect the presence or absence of a particular analyte of interest in a test sample. Test samples that can be used include urine, serum, blood, saliva, and other biological fluids. The types of analytes that can be detected include infectious agents (such as bacteria and viruses), proteins, non-proteinaceous agents, chemicals, drugs, and the like.
In some typical test strip systems the sample to be tested (i.e. the test sample) is applied to a sample pad located towards one end (the proximal end) of a test strip. After application, the test sample (or components of the test sample) flows laterally through the sample pad and into an adjacent conjugate pad distal to the sample pad. The conjugate pad typically contains conjugates comprising an antibody specific to the analyte of interest conjugated to a labeled/detectable particle. After flowing through the conjugate pad the test sample then flows into an adjacent test membrane distal to the conjugate pad. The test membrane typically has two capture areas—a control capture area and a test capture area. The test capture area typically contains an antibody that is immobilized on the test membrane and that can bind to the analyte of interest. As the test sample flows through the test membrane from the proximal end to the distal end, complexes containing the analyte of interest bound to a labeled conjugate will accumulate at the test line. The control capture area typically contains an antibody that is immobilized on the test membrane and that can bind to the labeled conjugates. As the test sample flows through the test membrane labeled conjugate molecules will accumulate at the control line. The accumulation of these complexes and/or conjugates at the test and control areas can be visualized as a result of the detectable label in the conjugate molecules, which may result in, for example, the appearance of a colored line.
There are a wide variety of different test strip systems that can be used for a wide variety of different diagnostic applications. For example, some test strip systems use a direct con-competitive antibody reaction scheme, while others use an indirect competitive antibody reaction scheme. Similarly, different test strip systems can be used for different types of test samples (such as blood, serum, urine, and the like) and for detection of different types of analytes (such as proteins, infectious agents, drugs of abuse, and the like). Regardless of the details of the test strip system, in practice, diagnostic test strips are frequently provided inside a housing (also referred to as a cassette or cartridge) that is made of plastic or some other suitable material. Such test strip housings typically have at least two types of openings. The first type of opening is a sample port—through which the test sample can be applied to the sample pad portion of the test strip using a pipette or similar device. The second type of opening is a result viewing port—through which the test and/or control areas of the test membrane can be viewed.
Prior to the present invention test strip housings were typically provided with a small sample port configured to allow application of a test sample to the sample pad area of a test strip using a pipette or some other similar device. Using these prior systems a test administrator would typically have to obtain a test sample, such as blood, from a patient and then transfer that test sample to the sample port of a test strip housing a pipette, a dropper, a syringe, a needle, or the like. The need to handle and transfer the test sample in this way increased the risk that test administrators or others could come into contact with a spilled or inaccurately placed patient sample or with a contaminated pipette. In addition, prior to the present invention test strip housings were typically provided with sample ports and result viewing ports that were open/uncovered such that it could be possible for a test administrator or other person to come into contact with a contaminated test strip. Furthermore, these prior test strip systems resulted in the generation of additional hazardous waste in the way of used/contaminated pipettes that required special disposal systems and careful handling.